WO1988008291A1

WO1988008291A1 - Chest compression apparatus

Info

Publication number: WO1988008291A1
Application number: PCT/US1988/001342
Authority: WO
Inventors: Warren J. Warwick; Leland G. Hansen
Original assignee: Regents Of The University Of Minnesota
Priority date: 1987-05-01
Filing date: 1988-04-26
Publication date: 1988-11-03
Also published as: ATE173606T1; EP0363380B1; US4838263A; JP2749091B2; EP0363380A1; DE3856266D1; JPH02503275A; AU610272B2; HK1014355A1; AU2466688A; EP0363380A4; DE3856266T2

Abstract

Oscillatory chest compression apparatus (10, 10') to aid in loosening and eliminating mucus from the lungs of a cystic fibrosis patient. The apparatus includes a mechanism (18) for applying pressurized air to a bladder (16) covering the chest of a person (12) and a mechanism for venting pressurized air from the bladder (62, 116). In addition, the apparatus includes a mechanism for supplying the air to the bladder in a regular pattern of pulses (22, 88). The application of the pressurized pulses and the pulse rate is controllable by the patient through means of the patient control value (162) and the venting tube (116).

Description

CHEST COMPRESSION APPARATUS

Field of the Invention The present invention relates generally to medic devices and, more specifically, to oscillatory che compression devices which aid in the loosening and elimin tion of mucus from the lungs of a person, particularly peop affected by cystic fibrosis.

Background of the Invention Cystic fibrosis is a deadly hereditary diseas With one in 20 people carrying the recessive gene, concepti of a child having cystic fibrosis results in approximate one in every 400 child-bearing marriages. No cure for t disease has been discovered. Cystic fibrosis affects t mucus secreting glands of the body so that there is overproduction of mucus. The lungs are continuously fill with the excess mucus, and it must be removed daily to reduc the build-up and the risk of infection. Presently, treatmen involves an aerosol therapy three or four times a. day obtain bronchial drainage and a daily physical pounding the chest wall to loosen mucus for expectoration. Dail treatment can range from four to six hours plus and necessi tates a . respiratory therapist or at least a ^'trained indivi dual to provide the pummeling of the chest.

The present invention rests on a premise derive from past research with dogs. Oscillating pressure aid mucus clearance in airways and concurrent vibration decreases the viscosity of the mucus thereby enhancing moti lity. The research on dogs made use of a modified bloo pressure cuff wrapped around the dog in the region of the ri cage. The air bladder in the cuff was pressurized by a oscillating pump.

The art in the area of mechnical vibrations to th body shows such things as inflatable jackets or garments t put on a person to aid in respiration, such as artificial respiration. U. S. Parent 3,043,292, U. S. Patent 2,354,397, U. S. Patent 2,588,192 are representative. Additionally, a garment which provides oscillations for the purpose of messaging the body is shown in U. S. Patent 3,310,050. The ar't, however, does not address the indicated cystic fibrosis treatment problem.

Summary of the Invention The present invention is directed to an oscillatory chest compression apparatus for a person which includes a mechanism for applying a force to the chest of the person. The force applying mechanism includes a bladder for receiving pressurized air. The apparatus also includes a mechanism for supplying a regular pattern of pulses of pressurized air to the bladder, a mechanism for venting the pressurized air from the bladder, and a mechanism for alternately controlling the pulse applying mechanism and the venting mechanism.

In the preferred embodiment, a rotary valve deter¬ mines the oscillation rate of air entering the bladder fro the pressure side and air evacuating the bladder from the depressurizing side. A first blower is used on the pressurizing side of the rotary valve, and a second blower may be used on the evacuation side to rapidly move the air. The bladder is held adjacent to the chest of a person by a shell which is fitted to and fastened about the person. control switch functions a solenoid valve on the pressurizing side of the rotary valve to stop pressurization during the inspiration portion of the patient's breathing cycle.

In an alternate embodiment, a primary bellows is oscillated to provide air to the bladder adjacent to the chest of the person. In addition, a secondary bellows is oscillated to fill an air reservoir which can rapidly fill the bladder after it has been emptied during an inspiration.

The inventive apparatus is a pioneering solution t the treatment problem faced by people having cystic fibrosis. The advantages of the invention relate to benefits derive from a treatment program utilizing the present apparatu rather than a conventional treatment program. In thi regard, a treatment program with the present apparatus provi des a cystic fibrosis patient with independence in that th person can operate the machine alone. He/she is no longe required to schedule treatment with a trained individual This results in increased psychological and physical freedo and self esteem. The person becomes flexible in his/he treatment and can add extra treatments if such would be bene ficial as in the case of fighting a common cold. An addi tional benefit is the vast decrease in cost of treatment. Brief Description of the Drawings The advantages and objectives of the present inven tion are explained with particularity hereinafter b referring to the drawings briefly described as follows:

FIGURE 1 is an illustration of a person operatin the alternate embodiment apparatus in accordance with th present invention; FIGURE 2 is a schematic diagram of an apparatus i accordance with the preferred embodiment of the presen invention;

FIGURE 3 is a schmatic diagram of an apparatus i accordance with the alternate embodiment illustrated i FIGURE 1; and

FIGURE 4 is an illustration of pressure pulse superimposed on an oscillatory curve representing a patient' breathing cycle.

Detailed Description of the the Preferred and Alternate Embodiments

Referring then to the drawings . wherein lik reference numerals designate identical or corresponding part throughout the several views, and more particularly to FIGUR 2, an apparatus in accordance with the present invention is designated generally by the numeral 10. With reference to FIGURE 1, an alternate embodiment apparatus is designated generally by the numeral 10*. In FIGURE 1, person 12 is shown wearing a shell 14 with an air vest or bladder 16 bet- ween the shell and his chest. A hose 114 connects the pulse pumping system 18 with vest bladder 16. Person 12 is shown with his left hand regulating switch 162 which controls the supply of air pulses to vest bladder 16, and with his right hand controlling the venting of vest bladder 16 by opening or closing the end of tube 116.

Preferred embodiment 10 could be illustrated simi¬ larly to FIGURE 1, except it is controllable with only one hand, as will become apparent. As shown in FIGURE 2, the air pulse system 18 of apparatus 10 comprises a pair of high volume regenerative blowers 26 and 62 having output which is controlled by a large bore rotary valve 22. The pressure side blower 26 has been tested using a commercially available unit capable of producing a pressure of 43 inches of water at a volume of 53 cubic feet per minute. Blower 26 is driven by a motor 27. The test unit was driven by a one-half hor¬ sepower AC motor at 1725 rpm. The evacuatio'n s^'ide blower 62 is driven by a motor 63. The test blower was capable of pro¬ ducing a pressure of 28.5 inches water at a volume capacity of 27 cubic feet per minute. The test blower was operated by a one-eighth horsepower AC motor at 1725 rpm. Preferably, the pressure side blower 26 is oversized relative to the eva¬ cuation side blower 62, as indicated with respect to the test units, to accomplish fast reinflation of vest bladder 16 after it has been evacuated. Alternate positive and negative pressures are applied to vest bladder 16 via a rotary valve 22. During the positive input pulse through valve 22 the negative pressure side of the system is closed. During the negative pressure pulse the positive pressure side of the system is closed. The rotary valve creates alternating positive and negati pressure pulses to vest bladder 16 and is driven by mot 53. During testing, a one-twentieth horsepower DC motor 5 controlled by a conventional DC controller 54 was used. electronic tachometer with a magnetic pickup was used monitor valve rotational speed. The blowers operated con tinuously, so that pulse speed was regulated by controlle 54.

A solenoid valve 24 is located between the positiv side blower 26 and the rotary valve 22. During testing solenoid valve 24 had a 1.25 inch bore and was operated by 2 volt power. Valve 24 is normally closed and is controlled b a patient held hand switch 30. In the open position a posi tive 43 inches of water pressurized air flow is applied t rotary valve 22 which in turn allows the air in the form of pressure pulse through to vest bladder 16. Since rotar valve 22 opens, and closes air flow between positive sid blower 26 and vest bladder 16, pulses are created. Th pulsing rate is determined by the rotational speed of rotar valve 22 which in turn is determined by motor controller 54. When solenoid valve 24 is in the closed position no air flow from the positive side blower 26 passes to ves bladder 16. Rather, vest bladder 16 is evacuated by negativ pressure side blower 62. Such evacuation reduces the effort required by a patient during inhalation. Some patients ma find a negative pressure is not needed to evacuate the ves "for comfortable inhalation. For such patients, the vacuum o negative pressure blower 62 is optional.

A manual flow valve 46 is located between positiv pressure blower 26 and vest bladder 16 to provide adjustmen for regulating the flow volume or pulse strength to ves bladder 16. Likewise, a manual flow valve 64 is located bet ween rotary valve 22 and negative side door 62 to provid control relating to evacuation. That is, for some patients total evacuation of vest bladder 16 may be unnecessary or undesirable. Since rotary valve 22 rotates at a constant speed and since negative side blower 62 operates at a constant speed, when flow valve 64 is set to constrict the flow communication line between rotary valve 22 and blower 62, it will in effect reduce the volume of air which is eva¬ cuated during a revolution of rotary valve 22. Therefore, depending on how long the pressure side of apparatus 10 is closed, complete evacuation by the evacuation side may not occur.

With reference to FIGURE 2, apparatus 10 is hereinafter described even more particularly. Pressure side blower 26 is in flow communication through hose 28 with nor¬ mally closed, solenoid valve 24. It is understood that any reference to a hose could as well be a pipe or other mecha¬ nism for directing air from one point to another. Solenoid valve 24 is in flow communication with rotary valve 22 through a flow control valve 46, preferably manually operable, wherein hose 44 connects solenoid valve 24 with flow control valve 46 and hose 48 connects flow control valve 46 with rotary valve 22. One or more lines shown as hose 50 connect rotary valve 22 with vest bladder 16. On the nega¬ tive pressure side, rotary valve 22 is in flow communication through flow control valve 64 with evacuation fan 62. Hos 66 connects rotary valve 22 with flow control valve 64, while hose 68 connects valve 64 with fan 62.

AC motor 27 drives pressurizing fan 26 and is con¬ nected via electrical lines 70 and 72 to electrical power source 42. AC motor 63 drives evacuation fan 62 and is con- nected via lines 74 and 76 to power source 42. DC motor 53 is connected via lines 57 and 58 with controller 54. Controller 54 includes a manual control 56 for varying spee of motor 53. Motor controller 54 receives power via lines 59 and 60 from source 42. Solenoid valve 24 is connected through an isolati transformer 36 to power source 42. More particularly, sol noid valve 24 is connected to one side of transformer 36 v line 38 and to the other side of transformer 36 via lines and 34 through patient control switch 30. The other side transformer 36 is connected to power source 42 via lines and 41.

A cystic fibrosis patient is generally weak and h a weak cough and cannot clear mucus from his/her lungs, som times hardly at all. A high frequency vibration aids decreasing the viscosity of the mucus, freeing it from lu walls and thus making it much more likely that a weak coug will be able to clear mucus. As some mucus is cleared, t cough will likely strengthen thereby allowing more and mor mucus to be cleared.

A more graphic representation is shown in FIGURE 4 The lower frequency line 78 represents the breathing cycle o the patient. The higher frequency line superimposed on por tions of the low frequency line represents the pulsing motio administered by vest bladder 16 to the patient's chest.

Initially, the patient breathes rather shallow an uses only a small percentage of his/her total lung capacit as represented by the region between .the inspiratory reserv capacity line 82 and the expiratory reserve capacity line 84 As some mucus clears, the patient begins using a greater per centage of his/her lung capacity. A treatment goal is to ge the patient breathing so deeply that he/she reduces his/he residual volume as represented by line 86, thereby increasin his/her vital capacity. To use apparatus 10, first a vest bladder 16 and shell 14 are custom made for the particular patient 12. Th vest bladder 16 must cover the region of the chest whic covers the lungs. The vest bladder has a single air chambe with at least one and preferably two air ports located near the upper portion of the chest. The vest, on a test model, was made of 15 mil polyurethane with hook and loop closures in front.

Shell 14 may be any one of several possible types. For example, the hard shell may be made from a polypropylene body cast to have split sides to allow for an easy fit. On the other hand, shell 14 may be made as a soft vest from a non-stretch cloth material. Or, shell 14 may be made of nonstretch cloth material, but made to have front and back panels forming pockets to receive rigid polyproplyene plates. All shell types preferably include hook and loop closures.

After the patient has been fitted with a vest bladder 16 and shell 14 such that vest bladder conforms to the patient's chest snugly, but not tightly, hose 50 is con- nected thereto. The three motors 27, 53 and 63 are then turned on. Since solenoid valve 24 -is normally closed, fan 26, although not_, operating, is not yet pressurizing .vest - bladder 16. Evacuation fan 62, also now operating, is func¬ tioning to evacuate vest bladder 16. The patient then closes switch 30 which opens solenoid valve 24 - and allows for pressurization of vest bladder 16 and does so. with air pulses at a frequency set^' by control 56 of motor controller 54. If the volume of air from either the pressure side or the eva¬ cuation side of the system is too great or not enough, hand control valves 46 and 64- are appropriately functioned.

With the system operating, the patient must learn to control apparatus 10 in accordance with his/her breathing cycle. That is, switch 30 must be held down during expira¬ tion and released during inspiration so as to provide pulsing during expiration and evacuation during inspiration. The effect is shown graphically in FIGURE 4 by the smooth line 78 directed toward inspiratory reserve capacity line 82 and th superimposed wavey line 80 on line 78 directed toward expira¬ tory reserve capacity line 84. The high frequency pulse rate appropriate for any particular patient is obtained by empir cally measuring either the flow rate or the volume of a breathed by the patient at different frequencies and at di ferent time durations of the treatment with apparatus 1 The present apparatus is particularly advantageous in th regard since the pulsing frequency can be tuned to a pa ticular patient to optimize energy transmission to the lung Typically, the breathing cycle is a relatively low frequen and for a healthy person is commonly about .2 to .4 hert For a person having cystic fibrosis or other sickness, t breathing frequency may range up to one or two hertz. T high frequency pulsing is generally tuned between 10 to 3 hertz and .could- go as high as the 30 hertz rate for a smal child. In any case, the low frequency breathing cycle wil be below 5 hertz, while the high frequency pulsing cycle wil be above 5 hertz.

It is noted then that the preferred embodimen apparatus provides a patient a number of advantageo features. Compression pulsing is applied to the entir chest. Pulsing frequency may be tuned for optimal energ transmission. Apparatus 10 is patient controlled. If th patient drops switch 30, apparatus 10 simply evacuate pressure.

An alternate embodiment of apparatus 10 is depicte in FIGURE 1, as indicated. Apparatus 10' is shown schemati cally in FIGURE 3.. The pulse pumping system comprises a pai of bellows 88 and 90 which may be air ride springs of a typ commonly used for suspension of large vehicles. Bellows 8 and 90 operate in opposite directions. Bellows 88 and 90 ar driven by a one-half horsepower DC electric motor 92 con nected by a five millimeter timing belt 112 to a centrall mounted crankshaft 96. The timing belt runs in conjunctio with a pair of pulleys 108 and 110. The crankshaft is hel in position by bearing pillow blocks 98 and 100. A D variable speed motor controller 142 is used to regulate moto speed. The primary bellows 88 is in direct fluid commun- ciation with the vest bladder 16 on the patient. Air is compressed in and evacuated out of the vest by the primary bellows at a rate of typically 10 to 30 hertz. The volume of the pulse is calibrated to patient size and is dependent on the length of the pump stroke and the diameter of the bellows.

The secondary bellows 90 provides an additional airflow to vest bladder 16 which allows the patient to regu- late vest bladder contact pressure. This has importance since little or no pressure is needed or in fact desired while the chest wall is expanding during inspiration as pre¬ viously discussed. Therefore, during inspiration air in the vest bladder is vented to atmosphere, and after inspiration a rapid reinstatement of pressure is necessary for effective chest compression before the next breathing cycle begins. The secondary bellows 90 has directional air flow through a series of one way valves to a small air storage tank 130-. The pressure of the air storage tank builds to about one psi during patient inspiration, while the air vest bladder 16 vents to atmosphere. The patient regulates the pressure of the vest bladder by covering or uncovering a vent hole on air hose.116 with _.a finger. When the vent is open, air is vented to atmosphere. When the patient closes the vent hole and also-closes switch 162 controlling solenoid valve 132, the compressed air in the air tank is dumped into the inflatable vest bladder. Such action provides quick reinflation .of the vest after the patient has finished inhaling to achieve a contact pressure which is efficient for effective oscillatory chest compression.

More particularly, apparatus 10' as shown in FIGURE 3 includes primary bellows 88 and secondary bellows 90, both of which are driven by DC motor 92. On the sides facing away from one another, both primary and secondary bellows 88 and 90 are held by identical base members 92 and 94. Each ba member 92 and 94 presents a flat solid surface against whi the bellows 88 and 90 may be compressed. Crank shaft 96 i supported by bearing pillow blocks 98 and 100. Connectin rods 102 are appropriately attached to crank shaft 96^' at on end and at an opposite end may be attached through a univer sal joint 104 to a plunger 106. It is understood that th present description relates only to functional components, an that structural framework is necessary and may be easil envisioned and constructed by one skilled in the art Pulleys 108 and 110 fasten to crank shaft 96 and the shaf of motor 92, respectively, to support timing belt 112.

Primary bellows 88 is in fluid communicatio through tube 114 with vest bladder 16. Tube 114 includes branch tube 116 with an open end 118 which the patient close when' he/she wants pressure in vest bladder 16 and opens whe he/she wants to vent vest bladder 16. Secondary bellows 9 receives make up air through tube 120 having a one way chec valve 122 open in a flow direction leading toward secondar bellows 90. Secondary bellows 90 is also in fluid com munication through tube 124 with one way check valve 12 leading in a flow direction away from secondary bellows 90 Valve 126 is in fluid communication through tube 128 with ai storage tank 130. Air storage tank 130 is in fluid com munication with tube 114 through solenoid valve 132 and on way valve ,134 providing flow only in a direction^' away fro storage tank 130, via tubes 136, 138 and 140. When solenoi valve 132 is open, air from storage tank 130 flows to eithe or both primary bellows 88 and vest bladder 16. In par ticular, make up air for primary bellows 88 is supplied b vest bladder 16 or storage tank 130.

Motor 92 is electrically connected with controlle 142 via lines 144 and 146. Controller 142 is connected t power source 148 via lines 150 and 152. Solenoid valve 132 is isolated from power source 148 by transformer 154. The primary side of transformer 154 is connected to source 148 via lines 156 and 158. The secondary side of transformer 154 is connected to solenoid valve 132 via line 160 and through patient controlled switch 162 via lines 164 and 166.

To use, as with the preferred embodiment firstly the vest bladder and shell 16 and 14 are fitted on patient 12. The patient places one hand at the end of tube 116 and the other hand holds switch 162. Motor 92 is started and regulated to a desired speed in a fashion as described with respect to the preferred embodiment apparatus^" 10 ' using motor controller 142. The patient must then learn when to apply compression relative to his/her breathing cycle. That is, during expiration, the patient opens switch 162 and closes end 118 of tube 116. During inspiration, it is generally desirable to vent vest bladder 16 so that the patient then opens switch 162-and opens end 118 of tube 116.

Thus, although both the preferred and alternate embodiments of apparatus 10 provide pressure pulses to the chest of a patient and allow the patient controls the rate of the pulses and the application of the pulses, it is apparen that the actual components of the two systems are substan¬ tially different. In this regard, it is understood then tha even though the advantages and details of structure and func- tion of the preferred and alternate embodiments have been se forth, they are nevertheless exemplary and other equivalents are possible. Therefore, changes made, especially in matters of shape, size and arrangement to the full extent extended b the general meaning of the terms in which the appended claims are expressed, are within the principle of the present inven¬ tion.

Claims

WHAT IS CLAIMED IS:

1. Oscillatory chest compression apparatus for a pe son, comprising: means for applying a force to the chest of sa person, said force applying means including a bladder f receiving pressurized air; means for supplying a regular pattern of pulses said pressurized air to said bladder; means for venting said pressurized air from sai bladder; and means for alternately controlling said puls supplying means and said venting means.

2. Apparatus in accordance with claim 1 wherein sai force applying means also includes a shell which said perso

• wears to limit outward expansion of said bladder so that sai bladder forces inwardly on said person's chest.

3. Apparatus in accordance with claim 1 wherein sai pulse supplying means includes a primary bellows; first means for communicating air between said pri mary bellows and said bladder; means for providing air to said primary bellows and primary means for reciprocating said primar bellows between expansion and contraction configuration thereby creating pulses of pressurized air.

4. Apparatus in accordance with claim 3 wherein sai air providing means includes: a reservoir for pressurized air; second means for communicating air in a one-wa direction from said reservoir to said primary bellows; a secondary bellows; third means for communicating air in a one-way direction from said secondary bellows to said reservoir; means for inletting air to said secondary bellows; and secondary means for reciprocating said secondary bellows between expansion and contraction configurations.

5. Appartus in accordance with claim 4 wherein sai venting means includes an outlet port in said first com- municating means, said controlling means including means operable by said person for covering and uncovering sai outlet port.

6. Apparatus in accordance with claim 4 wherein sai second communicating means includes a. one-way valve and .sai controlling means includes a stop valve installed in sai second communicating means and means operable by said perso for functioning said stop valve.

7. Apparatus in accordance with claim 1 wherein sai pulse supplying means includes: a pressurizing blower; - a rotary valve and means for driving said valve; first means for communicating air between sai pressurizing blower and said rotary valve; and second means for communicating air between sai rotary valve and said bladder.

8. Apparatus in accordance with claim 7 wherein sai venting means includes a depressurizing blower and thir means for communicating air from said rotary valve to sai depressurizing blower.

9. Apparatus in accordance with claim 8 wherein sai controlling means includes a stop valve installed in said first communicating means, said controlling means furthe including means operable by said person for functioning sai stop valve.

10. Oscillatory chest compression apparatus for a per son, comprising: means for applying a force to the chest of sai person, said force applying means including a bladder fo receiving pressurized air; means for alternately blowing air into and out o said bladder, said blowing means having pressurizing an depressurizing lines, said blowing means further including rotary valve alternately open and closed with respect to eac of said pressurizing and depressurizing lines; and means •for switching the pressurizing line of sai blowing means on and off.

11. A method to aid a person in clearing mucus fro his/her lungs, comprising the steps of: restraining a bladder adjacent said person's chest alternately cycling pressurized air pulses int said bladder at a relatively constant rate and evacuatin said bladder, said cycling being,in rhythm with said person' breathing, said bladder evacuation allowing inspiration b said person, said pressurized air pulsing in said bladde mechanically pounding said person's chest to free mucus i said person's lungs.

12. The method in accordance with claim 11 wherein sai cycling step includes said person operating a switch t control administration of said pressurized aid pulses to sai bladder and said evacuation of said bladder.